Well survey instrument



Oct. 3, 1933. JOHILJSTQN 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15. 1950 8 Sheets-Sheet 1.

-IloY 22 'INVENTOR [Vorrzs dolmszozz BY M W ATTORNEY.

Oct. 3, 1933. JOHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15, 1930 8 51166125 8118 2 OOOQOOOOOOOOOOOOOOO INVENTOR. Norms Johnsi'on N. JOHNSTQN WELL SURVEY INSTRUMENT 1 Oct. 3, 1933.

8 She ets-Sheet 3 Filed Oct. 15. 1930 INVENTOR. Norms Johnafon BY f 54 ATTORNEY.

Oct. 3, 1933. N. JCHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15, .1950 8 Sheets-1311691; 4

is Q W// UDEIDD DUI I INVENTOR. Norms Johns fan ,0" M ATTORNEY.

Oct. 3, 1933. JOHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15, 1930 8 Sheets-Sheet 5 INVENTOR. Norris Johnszon p Q 5 MW ATTORNEY.

Oct. 3, 1933 I N. JOHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15, 1930 8 Sheets-Sheet 6 INVENTOR. Norm-s Jo hnsfoz Oct. 3, 1933. N. JOHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. '15, 1930 8 Sheets-Sheet 7 INVENTOR. NOZ'TLS Johns ion BY 4 2 M f ATTORNEY.

Oct. 3, 1933. N. JOHNSTON 1,928,970

WELL SURVEY INSTRUMENT Filed Oct. 15. 1930 8 Sheets-Sheet 8 Cyc/e One Pena /um Vo/faye Earf/v /n 0 0 c for INVENTOR. Norris Johnsion f fl/ ATTORNEY.

Patented Oct. 3, 1933 UNITED STATES 1,928,970 WELL SURVEY INSTRUMENT Norris Johnston, Long Beach, Calif., assignor to Union OiI'Company of California, Los Angeles, Calif., a corporation of California Application October 15,

22 Claims.

This invention relates to devices for surveyin the trend of bore holes especially of the type produced in deep well drilling, wherein as is well known a departure from the straight and vertical is the rule rather than the exception. I

Fundamentally the object of the invention is to provide apparatus by means of which both the inclination and the direction of inclination of a bore hole maybe measured and progressively indicated at the surface as a device is lowered in the hole successively from one position to another. Primarily all measurements are made electrically and are then successively conducted to the surface and transformed into mechanical energywhereby curves are continuously recorded for each position in which the device is placed in the well, in order that the record of the well conditions may be observed substantially at the time that the measurements are made.

Briefly stated the apparatus of the present invention comprises surface mechanism and an instrument adapted to be lowered into a well bore. The well instrument contains an earth inductor compass, a rotatable mounting carrying a pendulum free to swing in a plane parallel to the axis of the mounting and across a resistance element, a synchronous motor for driving the compass and the pendulum mounting, and a rotary arm driven in unison with the pendulum mounting and in contact with a conducting ring connecled in electrical serieswith the pendulum and its resistance, said ring having an interruption gap in the form of a segment of insulation for interrup'ing the current during each revolution. The surface mechanism comprises a synchronous motor generator for energizing the synchronous motor in the well instrument, a commutator for the earth inductor current, means for adjusting for the phase angle between the synchronous drive and the earth inductor current, means to record said angle, and means for transforming electrical energy into mechanical energy and for continuously recording curves showing the current changes and indicative of conditions in the well instrument. In a preferred embodiment the transforming means is in the form of a galvanometer relay and a reversible motor controlled by the relay and actuating the recording means.

The invention may be broadly stated as comprising the employment of an instrument adapted to be lowered into a bore hole, the instrument including an earth inductor compass for indicating and determining directional relations, in combination with a rotated pendulum which is 1930. Serial No. 488,844

free to swing across a resistance into the plane of maximum inclination during each rotation period of the pendulum for correspondingly modifying an electric current. The invention also includes means, such as the interrupter device, to modify a pendulum current for orienting pendulum position with respect to a point having a known or determinable position, particularly a fixed point on the instrument housing. The invention may be otherwise stated as covering a well survey instrument adapted to be lowered into a well comprising a rotating shaft, a gravity operated member movable into the plane of maximum inclination, a rotating member driven by said shaft for orientation of pendulum position, a circuit in which said members are connected, and an interruption element cooperating with one of said members to produce indicative breaks in current flowing in the circuit. Theemployment of multiple switches to shift the measuring circuits with proper relation to the pendulum and compass movements for separately indicating these movements at the surface, also is of this invention. The invention may further-be said to reside in the method of generating curves representative of the electric currents, in modifying these curves in accordance with the inclination of the bore holes at any given point under measurement, and in further modifying these curves with respect to a magnetic north for proper orientation of the direction of. inclination.

In the accompanying drawings, wherein one embodiment of the broad invention is disclosed simply by way of illustration:

Fig. 1 indicates the measuring instrument per se in operative position within a well, the surface mechanism for supplying power to the surveying instrument, and for receiving the modified current impulses from the instrument and for transforming said impulses into mechanical energy and producing a record, being indicated diagrammatically;

Fig. 2 is a vertical section through the casing and containing mechanism constituting the surveying instrument;

. Fig. 3 is an enlarged sectional detail showing in elevation the major parts of the survey instrument and the electric connections;

Fig. 3a is a cross section on line 3a--3a of Fig. 3;

Fig. 4 is a plan of the surface mechanism;

Fig. 5 is chiefly a side elevation taken from the line 5-5 of Fig. 4-;

Fig. 6 is a vertical sectional "detail taken from the line 6-6 of Fig. 4;

Fig. F1 is a front end elevation taker. 7-? of Fig. 4;

Fig. 7a m a detail in section of parts shown in I Fig. 8 is a diagrammatic representation of the complete system of mechanical drives contained in the surface mechanism;

Fig. 9 is a wiring diagram of the well instrument;

Fig. 10 is a wiring diagram for the surface mechanism;

Fig. 11 is a wiring diagram of the power circuit for the pendulum and resistance elements of the well instrument;

Fig. 12 is a wiring diagram for the pendulummovement circuit;

Fig. 13 is a wiring diagram for the pendulumvoltage circuit;

Fig. 14 is a wiring diagram for the earth inductor compass;

Fig. 15 is a record of a complete cycle produced by the present apparatus; and

Fig. 16 is illustrative of calibrating charts required to be used to correct errors due to the sharp angle to the horizontal of the earth's magnetic lines in the various localities.

Before considering the structure in detail and in its logical order it will be helpful first to consider the general construction broadly in order that the general relation of the primary parts and their functions may be better understood when taking up the detailed narrative.

Briefly described, the preferred construction herein disclosed employs a Wheatstone bridge, of

which two arms R1 and R: are located in the well and two arms R: and R4 are provided at the surface. The two arms R1 and R: within the well are in the form of a resistance coil or the like across which a pendulum P is adapted to swing, the

pendulum and said resistor together with a housing in which they are carried being continuously rotated so that during each cycle the pendulum swings in the plane of maximum inclination across the opposite arms R1, R: of the bridge to the extent of such maximum inc ation, whereby a sine curve of voltage intercep by the pendulum may be recorded at the surface whose amplitude will be a direct measure of the inclination of the axis of the instrument from the vertical. At the surface a galvanometer relay G is employed in conjunction with the two upper arms Ra, R4 of the Wheatstone bridge, whereby current variations through the bridge circuit will cause actuation of the galvanometer needle. This galvanometer relay, whose construction and operation are well understood, actually amounts to a galvanometer-operated automatic switch. This switch controls current to a reversible motor H. Thismotor performs two functions:

a.To shiftacontact33acrossthearmsRz and R4 (which are in the form of a toroid coil) thereby balancing the circuit and b. To drive a mechanical recording rack 48 and pen 50 in exact proportion to the amount of ad- Justment of the contact 33.

The driving mechanism for the entire apparatus .is in the form of a primary motor L provided at the surface and connected to drive a synchronous generator 5.

The synchronous generator 8 furnishes electric power to a synchronous motor 12 dlspoud within the instrument casing A which is adapted to be lowered into the well. This casing A, which is of sumcient length to assume parallelism with the axis of that portion of the hole in which it is positioned, the pendulum P which together with housing and resistance R1, R1 is adapted to be constantly rotated by the synchronous motor 12.

The important parts of the surface mechanism, which is generally indicated-at B, are the synchronous drive motor L, the synchronous generator S which actuates the synchronous well motor 12, a toroidal coil 32 composed of the arms R3, R4, which together with adjustable contact 33 constitute the upper half of the Wheatstone bridge, a multiple switch such as a drum switch D for the various circuits, the reversible motor M, the recording rack 48 and pen 50, a record chart C, and an adjustable synchronous commutator for an earth inductor current received from an earth inductor coil 10 in the well instrument A presently to be described, said commutator being adapted to adjust for the phase angle between its position and the earth inductor voltage.

The important parts contained in the well instrument A, are the pendulum P, the synchronous motor 12, an interruptor 21, 22, 23, an earth inductor coil 10, and a multiple switch such as a drum switch D. The interruptor is located in the pendulum circuit and has its interrupter gap 21 fixed with relation to the casing A, such gap being passed by a contact 22 rotated in unison with the rotation of the pendulum and its housing. The position of this gap is definitely located, for example in the magnetic north, before the instrument is lowered into the well. The earth inductor coil 10 which is rotated at high speed from the synchronous motor 12 isconnected with the synchronous commutator 80 at the surface.

Before the instrument is lowered into the well, the parts being in operation, said synchronous commutator is adjusted to show a zero phase angle between the earth inductor current from coil 10 and the position of said commutator ao. Thus working opposite a fixed reference point may be used to indicate the amount of adjustment, thereby serving to orient the instrument housing A in the well with respect to its interruptor gap 21 and magnetic north.

The drum switches D and D operate in unison and serve to cut the various circuits in and out both inthesurfacemechanismBandinthewell mechanismAinorderthatasinglepairoflead lines 1V and V may serve for several measuring circuits. This makes it nccesary then to employ in addition only those wires I, II, III which serve to drive the synchronous well motor 12 from the synchronous generator 8 at the surface. Current for the pendulum circuit is conveniently taken through a transformer, rectifier and filter from the power line supplying the synchronous motor 12.

Dunn. Dlscurnon The surveying mm 'I'hesurveyinstrumentwhichisadaptedtobe loweredintothewelliscontainedinacasingliof suilicient length that when positioned within any portion of the hole being measured its axis will assume a position substantially parallel with the axis of the hole somewhat as indicated in Fig. 1.

This housing A contains an earth inductor coil which is merely an elongated flat open coil mounted for high speed rotation about its longitudinal axis. It is driven through a suitable gear reduction 11 by a synchronous motor 12 supplied with electrical energy from a motor-generator set L, S of the surface mechanism B through the medium of appropriate power lines I, II, III. By means of a second gear reduction 13, the motor 12 drives a pendulum housing 14 at'a comparatively low rate, for example 2 R. P. M. Both the motor 12 and the pendulum housing 14 are journaled in suitable partitions or brackets 16 within the casing A. Said housing 14 is provided with a transverse vertical s'lot 1'7 in which a fiat diamondshaped pendulum P is adapted to swing, said pendulum being pivoted within the housing as indicated at 18 and being mounted in such manner that a circuit may be completed through it to a contact 19 on its lower corner. This contact is adapted to travel along an arcuate resistance coil or other suitable resistor which may be considered to have two arms R1 and R2 at the opposite sides of said contact 19. Thus, when the device is inclined to the vertical and as the pendulum housing 14 is rotated, the contact 19 will travel into the plane of maximum inclination increasing R1 and decreasing R2 when the one sideof said housing 14 is on the low side, and again into the plane of maximum inclination decreasing R1 and increasing R2 when the opposite side of said housing 14 is on the low side. Below the pendulum housing 14 the casing A has fixed thereto a ring 20 in which is embedded a spot or insert of insulation 21 adapted to be traversed by a contact 22 which is caused to travel around the ring 20 by reason of the rotation of the housing 14 whose shaft 14 carries on its lower end a contact arm 23 provided with said contact 22. By means of the lead wire 24 and suitable slip rings and brushes 25, said ring 20, contact 22 and arm 23 are placed in circuit with the pendulum P and the resistance arms R1 and R2. This circuit however is broken when the contact 22 passes across the interruption gap formed by the insulation21. Thus said contact 22 and the arm 23 working in conjunction with the interruption gap 21 constitute an interrupter for the,

pendulum circuit; this term interrupter will be used hereafter in referring to this part of the structure. A lead line 24 extends from the ring 20 to a multiple drum switch D driven by the motor 12 through the medium of the shaft 14' and a suitable gear reduction 26. The top ring of the drum switch is connected with the measuring line V whereby the line 24' serves at the proper interval to lead the pendulum-movement circuits to the surface. The period of rotation of the drum switch D is that of a complete cycle of the apparatus, for example two minutes, and it serves to connect at proper intervals the various circuits to be measured with two measuring lines IV and V leading to the surface equipment.

In order that the opposite ends of the two resistance arms R1 and R2 which constitute the lower half of the Wheatstone bridge, may have a suitable voltage impressed thereon, lead. lines 2''! and corresponding slip rings and brushes 28 lead from the ends of said resistance arms to a source of low voltage current (-forexample five volts), which may be supplied either by a battery contained within the housing A- or by means such as-indicated comprising a transformer t, rectifier r, condenser c, and choke coils k. Connections 27' lead to the measuring line IV and to the drum switch D to which the'measuring line V is connected as above indicated, whereby the total cuit 27, 27', and the earth inductor circuit 29, 30.

The surface equipment The currents carried by the measuring lines IV and V are conducted to the surface and led into a drum switch D which is the counterpart of the drum switch D of the well instrument A. Thus, the pendulum currents are passed from the drum switch D through galvanometer relay G to the arms R3 and R1 of a circular or toroidal potentiometer coil 32 across which a contact 33 is adapted to be moved through the direct influence of a reversible motor M. Arms R2 and R4 of the toroidal coil 32 cooperate with arms R1 and R2 of the pendulum resistance in the well to constitute the Wheatstone bridge in which the contact 33 and the pendulum contact 19 are movable to vary the resistance of the four arms, the galvanometer relay G being connected in circuit between said contacts. A storage battery SB is provided to impress upon the arms R3 and R4 exactly the same potential (e. g. 5 volts) as that impressed upon arms R1 and R2 in the well by the transformer t. The needle of said galvanometer relay G swings between two contacts 34 to control a fixed voltage to a reversible motor M which is supplied from power lines also supplying a main drive motor L presently to be described. Motor lvfis thus energized for forward or reverse movement according to the control of the galvanometer relay G and serves to adjust the contact 33 correspondingly along the arms R3 and R1 of the toroidal coil 32. The mechanical movement of the contact 33 by the motor M is obtained by means of a worm 41 on the motor shaft, said worm meshing with a worm gear 42 journaled at 43 and having a geared hub 44 near the periphery of which the contact 33 is mounted. The contact 33 serves to connect the bare portions of the coil 32 which it engages With a slip ring 45 carried by and insulated from coil 32, said slip ring being connected by a lead 46 with the stone bridge. In this fashion the amount of rotation of the motor- M forward and reverse constitutes a measure of the movement of the pendulum P across the arms R1 and R2. A record of this motion is obtained by causing the geared hub 44-tc drive a gear rack 43 which extends along a guide 49 to the opposite side of the apparatus and carries at its end a recording pen 50. The pen 50 is thus moved across a record chart C which is slowly advanced simultaneously as hereinafter developed. Spring pressed rollers 52 serve to retain rack 48 in its guide and thereby maintain recording engagement of the pen.

The main drive motor L is direct connected to drive a synchronous generator S, thus forming a motor generator set which as previously indicated is connected through the power lines I, II, and III with the synchronous motor 12 located within the well instrument housing A, whereby the motor 12 necessarily operates in synchronism with generator S. The motor shaft L of said motor L is provided with a spiral gear 55 engaging a second spiral gear 56 which drives a shaft 57 having on its upper end a worm 58, driving a worm gear 59 mounted on a horizontal shaft 60 known as the drum-switch drive shaft since it carries a worm 61 driving a worm gear 62 on a drum shaft 63 provided with a plurality of contact rings 64 constituting the drum switch D. This drum switch D is rotated at the same rate as the drum switch D in the well instrument A, and serves through the medium of a plurality of spring contact fingers 65 mounted on an insulating post 66 to connect the various circuits at proper "intervals. An extension of the drumswitch drive shaft 60 beyond a vertical partition wall W carries a gear '70 meshing with other suitable gearing 71 having proper speed reduction values and connected to drive a paper roll 72 for moving a record sheet C with its record chart across a suitable platform beneath guide rolls 75. Thus as the recording pen 50 on rack 48 is reciprocated through the agency of the reversible motor M a record curve of the operations within the well is recorded upon the slowly moving chart C.

In order that the earth inductor current furnished from the earth inductor coil 10 in the well instrument A may be commutated, a synchronous commutator is provided. This commutator is mounted upon a rotating shaft 81 driven at identically the same speed as the earth inductor 10 from the shaft 5'7 by a gear train 82, 83. Spring feed brushes 84 and take-off brushes 85 are mounted on adjustable insulating arms 86 arranged parallel with the axis of the commutator drive shaft 81, said arms being carried on a head 8'? which in turn is carried by a depending shaft 88 journaled in the super-structure. Said shaft 88 is provided with slip rings 89 connected with the brushes 84 and 85, these slip rings being engaged by spring brushes 90 carried on an insulating post 91 and connected to suitable leads 92. The commutator brushes 84 and 85 are adapted to be adjusted to correct for any phase angle which may develop, as at starting, between the earth, inductor current and the position of the synchronous generator S and synchronous motor 12. The phase position of the generator S and motor 12 is represented by the position of said commutator 80 with respect to its brushes 84, 85, since said commutator 80 is driven directly from the drive motor L. Adjustment of the commutator brushes 84 and 85 is accomplished through the medium of an adjusting shaft 93 carrying a worm 94 engaging a worm gear 95 on shaft 81, said adjustment shaft 93 being actuated manually by a hand wheel 96 conveniently positioned above the chart C.

In order that this commutator adjustment may be accurately made and may be measured and recorded, a galvanometer 100 and a filter 101 (Fig. 10) are connected in circuit with the commutator 80, and the hand wheel 96 is employed to cause the'shaft 93 and its worm 94 to vniove the shaft 81 and the brushes 84 and 85 until the i sane galvanometer 160 reads zero. The earth inductor circuit and the commutator are now in phase, and the angle through which the brushes 84 and 85 have been moved represents the amount of angular displacement of the instrument housing A, and consequently of the interruption gap 21 in the well instrument A from the magnetic north, assuming that the original or zero position of said gap was in the magnetic north. For the purpose of indicating and recording the degree of this angular displacement a graduated circular scale is provided on a disc 105 frictionally mounted upon a worm gear 106 which is driven by worm 10'? carried by the adjusting shaft 93. Assuming a zero setting of the scale 105 opposite some fixed indicator such as a pointer 108, the gear 106 and disc 105 operate through a key and groove driving connection at 104 to drive a vertical shaft 109 mounted in a supporting bracket 110. Shaft 109 has secured on its lower v printing head or stamp whose reading will be taken from some fixed reference point or zero position such as the vertical diameter of its im pression when made on the record chart 0. Thus when the wheel 96 and shaft 93 are adjusted, the worm gear 106, the graduated disc 105 and stamp 111 are correspondingly adjusted. To take the reading of the stamp 111, a knob 112 on the upper end of the shaft 109 is depressed so that the position of the stamp is recorded on the chart. A spring 113 normally maintains the knob 112 and the stamp 111 in elevated position. The spring 113 also serves to maintain a sufficiently firm friction engagement between the disc 105 and the gear 106'to insure that the latter will drive the disc without slippage.

The reason for providing this friction drive between gear 106 and disc 105 is that when starting up the apparatus and preparing to lower the instrument A into the well with the interruption gap 21 in zero position, i. e. in the magnetic north, the brushes 84 and 85 must be adjusted by means of the wheel 96 to synchronize the earth inductor coil 10 with the generator S and the well motor 12. This therefore is the zero setting of the brushes, and it is necessary that the scale 105 and stamp 111 also -be set at zero. The latter addustment is accomplished simply by forcibly rotating the knob 112 and shaft 109 to move the disc 105 against its frictional engagement with gear 106 and to bring 0" opposite the pointer 108. The worm connection between gear 106 and worm 107 looks the shaft 93 against any such movement-as might affect the adjustment of the brushes 84 and 85. It is to be understood that this adjustment is made only when first placing the mechanism in operation preparatory to lowering the instrument A into a well.

It is also necessary to provide for an initial adjustment of the drum switch D' of the surface mechanism B in order to bring said switch into synchronism with the drum switch D in the well instrument A. Such provision is shown in PM. 6 where the worm gear 62 on drum shaft 83 is provided with one element of a clutch whose other element 121 is-flxed on the lower portion of said shaft 63, the latter being divided as indicated in order to provide for adjustment of the 'lower portion with respect to the upper portion.

A spring 122 serves normally to maintain clutch engagement. In order that the clutch part 121 and the lower portion of shaft 83 may be independently rotated to adjust the drum switch D, the lower clutch part 121 (whose hub is jour- .zaled in an adjacent bracket) is provided with a beveled gear 123 to be driven by a beveled gear 124 fixed on a shaft 125 journaled in any suitable bracket and provided with a hand crank 126 for rotation thereof. Thus, by rotating crank 126 and gears 1 23 and 124 the clutch part 121 will slip on the clutch part 120, the latter yielding sufilciently against the tension of spring 122. In this manner the drum switch D can be adjusted as much as required to bring it into synchronism with drum switch D in the well instrument A. A pointer 127 on thegear shaft 125 may be employed if desired to present a visual indication of the position of said drum switch D', the gears 123 and 124 having equal diameters to synchro nize the movements of pointer 127 and drum D. It is understood of course that, as in the case of brushes 84 and 85, this adjustment is employed only when placing the mechanism in operation and preparing to lower the instrument A into the well.

Operation In placing the mechanism in operation, the main drive or line motor L of the surface mechanism B (Fig. 4) is started, thereby rotating its shaft L' and the various gear trains connected therewith, and at the same time driving the synchronous generator S which thus supplies current to the synchronous motor 12 in the well instrument A. The motor 12 rotates the earth inductor coil 10, the pendulum housing 14, and the drum switch D. The instrument A is then turned to bring the interruption gap 21 into the magnetic north. Next, the adjusting crank 126 for the drum switch D' of the surface mechanism is then rotated to bring the rotation of said drum switch D into-synchronism with therotation of the drum switch D in the well instrument A. The attainment of such synchronism is indicated by visual observation of a voltmeter V (Fig. 10). When the voltmeter V indicates a high, steady voltage (approximately 5 volts) the drum switch D in the instrument A is on the segment known as Pendulum voltage", to give a check reading of the D. C. voltage supplied to the pendulum. When this steady 5 volt reading drops to zero, the Pendulum voltage segment of the drum switch D has just passed. A circular dial behind the pointer 127 is marked to show the exact position of drum switch D at all times. When the voltmeter V shows its sudden drop in voltage, the crank 126 is quickly turned so the pointer 127 indicates the appropriate position of drum switch D. A single pole, double throw switch is used to connect well cables IV and V to the voltmeter for this preliminary synchronizing, and the connection to the recorder is restored immediately for normal operation after this synchronizing is completed.

The next step is to adjust the hand wheel 96, shaft 93, and worm 94 to rotate the worm gear 95 and shaft 81 to so adjust the commutator brushes 84 and 85 with respect to the commutator 80 that the galvanometer shall read zero. The knob 112 on the angle recording shaft 109 is then rotated to move the graduated disc against its frictional engagement with the worm gear 106 to bring 0 opposite the pointer v108. These parts are now in zero position so that there is a zero phase angle between the current supplied by the earth inductor coil 10 and the position of the synchronous commutator 80.

The instrument A is then lowered into the well as by means of any suitable cable 150 attached R2, and the contact 33 on the toroidal coil 32 will maintain a middle position making the arms R3 and R4 of said coil 32 equal. The Wheatstone bridge represented by said arms R1, R2, R3 and R4 thus will be balanced and the needle of relay galvanometer G will be in zero position. Therefore as the record paper carrying the chart C advances, the recording pen 50 will inscribe a straight line upon said chart during that period when the drum switches D and D' are in position to connect the arms R1. Ra, R: and R4 with the measuring lines IV and V. Similarly if there has been no rotation of the instrument casing A to carry the interruption gap 21 out of the magnetic north, the galvanometer 100 will continue to read zero when the earth inductor current is cut in by switches D and D and no adjustment of the wheel 96 will be required. However when the drum switches D and D cut in the pendulum voltage by way of lines 27 and 27', the relay galvanometer G willbe operated to bring its needle into engagement with one of the contacts 34, thereby supplying current for corresponding operation of the reversible motor M which then operates through its worm 41,

worm gear 42, and hub gear 44 to drive the rack 105 48 and the recording pen 50 to inscribe upon the chart C a corresponding record of the pendulum voltage, as indicated in Fig. 15.

Assume now that the portion of the well hole into which the instrument A is next lowered is 110 at an angle from the vertical as in Fig. 1. As the pendulum housing 14 and the pendulum P are rotated the pendulum contact 19 travels slowly to and fro along the pendulum resistance R1 and R2 according as one side or the other is at the low side of the hole. When the drum switches D and D cut this pendulum-movement circuit in with the measuring lines IV and V, the needle of the galvanometer relay G moves into engage- Ri and R4 of the latter are in balance with the arms R1 and R2 in the well. Simultaneously the hub gear 44 moves the rack 48 to cause the pen 50 to inscribe a corresponding curve on the chart C, this curve approximating a sine curve as indino cated in Fig. 15. The amplitude of this curve on opposite sides of the zero or base line represents the degree of inclination. In practice two cycles of the pendulum motion are recorded, each cycle being for example of one-half minute duration and a complete rotation of the drum switches D, D requiring two minutes.

Assume next that, before the taking of the inclination reading as just outlined, the interruption gap 21 had rotated an appreciable numno ber of degrees around from the magnetic north. When the interrupter contact 22 on the interruption arm 23 passes over the interruption gap 21 during each cycle in which the pendulummovement circuit is operative, an interruption in the current flow will occur and a correspondingly sharp gap will be disclosed in each cycle of the sine curve as indicated at the points I. G. of the record of Fig. 15. Now, when the drum switches D and D cut in the current from the earth inductor coil m, the galvanometer 100 in circular stamp ill the erect direction :5 other sens, iicluouom coomutctc: the inductor coil i wheel 6 'iereiore turned to srfiust the som mute-tor M St, by way of the worm d worm gear Q5, golvo nometer reeds zero.

of pho- T adiustment at the some time be imparted by the wow to the worm gear lflfi and thence to the dusteal disc M35, and the degrees reed;

opposite e pointer lilfi will indicate the adjustme' thereby showing exactly how record now lee hown 7 chart rig.

Also, 'ne lines T and f were so c the top the sine cuwe represented the top side tlie inclinelie/ls. e sine represents two complete cycles Q1. toe movement or the pendulum P across resistance 3i and 3. Two cycles are recorded. as c i: and to lustre or complete record oi the motion case such sl'ioidcl loe either at the I or at L: e end oi the cycle. Each as considered the direction the movement of the paper represents lil" oi escli 360 cycle of pendulum rotation, eacli space considered vertically of the psper from the zero or base line represents 2 of inclination of the well hole. Thus the amplitude of the sine curve indicates an inclination of 2, ti s measurement being duplicated on each side of the base line by reason of he iact that the pendulum moves symmetrically, to the first shortening the arm R1 and then to the maximum shortening the arm R2 during the rotation of its housing 14. The interruption gap I. G. in each instance was about 42 to the right of the bottom side of the hole, or as represented by the record about 138 clockwise from the high toward the low side. But the reading of the orientation stamp ill was 189", showing that the interruption gap (and therefore the casing A and parts thereon) had 'movedin the hole to a position 189 clockwise from magnetic north. Since the interruption gap I. G. was 138? clockwise from the high side of the hole, and was also 189 clockwise from magnetic north, 8. direct subtraction of the former from the latter figure will, show that the high side of the hole is apparently 51 t to be expected from the actual ozim ction. oi the instrument is pa ticulcriy noticeable in case the unis the comes tlie actu direction of the is tied in fact when is ed'et an angle greater than the angle directi n of e vertical, 2i northerly ire ductor indication is soutlrezL, re otion of. cutting of l;

a; chart is s l. Reed recs-rd "71m r. L. H. its orientation cli cle, r

:7, .I. flnnc n qnqo r: Subtract Lou iiorn .Lwo roll a orientation.

0 a o. calibre clot C. Reed corrected t plane it of n It should be noted that cereto avoid nm'oiculty in the zero s oi the lvcuorneter we of the earth L uctor cult, in view of the fact that two cl metrically opposite positions of crushes and 35 will give readings. fllre identity these zero readmay be detected by noting the direction oi approach to zero of the gslvanometer when the lisncl wheel 98 is turned in a given constant direction, as clockwise. A convention must be adopted as to which zero will be used, and the some zero must always be used during a given set or measurements; otherwise N may register as El, or E as W.

is obvious that such incidental equipment as may be required to obtain desired readings and make desired adjustments can be employed without departing from the spirit of the invention. For example, since the storage battery S B is employed for the purpose of "1mpresslng the potential upon the surface arms R3 and R4 of the Wheatstone bridge exactly equal to the potential imposed upon the arms R1 and R: in the well it is convenient to employ the voltmeter on the measuring lines IV and V at the surface in order to visually check the voltage and make the required adjustment at thers'urface to avoid having to correct the amplitude on the chart due to'unbalanced voltages, as indicated by chart C and voltmeter V. Similarly if it be required to cut in a ground for the needle of the gslysncmeter relay G at certain times an additional ring may be employed at the lower end of the drum switch D.

It is to be understood that the disclosures herein are to be considered merely as illustrative and not as limiting, since many modifications within the scope hereof may be made by those skilled in the art.

I claim:

1. A well survey instrument comprising a rotating shaft, a pendulum cooperating therewith and movable into planes of maximum inclination, an orienting member rotated by said shaft for orientation of said plane, and an earth inductor compass having a rotatable element connected with and driven by said shaft.

2. A well survey instrument comprising a rotating shaft, a pendulum cooperating therewith and rotatably driven with the shaft and movable into the plane of maximum inclination, orienting means including a member rotated by said shaft for orientation of said plane, an electric circuit in which the pendulum and orienting member are connected for corresponding modification of current flowing therethrough, and a compass indicative of relative direction.

3. A structure according to claim 2 wherein the orienting means includes an interrupter for the current.

4. A structure according to claim 2 wherein the compass is an earth inductor compass.

5. A well survey instrument comprising a rotating shaft a pendulum cooperating .therewith and movable into the plane oi maximum I inclination, an orienting member rotated by said shaft for orientation of said plane, an electric circuit in which the pendulum and orienting member are connected for corresponding modification of current flowing therethrough, and an earth inductor compass having a rotatable element and a driving connection between said element and the rotating shaft.

6. A .well survey instrument adapted to be lowered into a well comprising a rotating shaft, a gravity operated member movable into the plane of maximum inclination, a rotating member driven by said shaft for orientation of pendulum position, a circuit in which said membersare connected, and an interruption element cooperating with the rotating orienting member to produce indicative breaks in current flowing in the circuit for purposes of orientation.

7. An instrument according to claim 6 wherein the orienting member is an earth inductor compass.

8. A well survey instrument comprising a rotating shaft, an orienting member constantly rotated thereby, a gravity member cooperating with said orienting member and movable into a plane of maximum inclination, an electric circuit in which said members are connected, an interrupter cooperating with one of said members to produce indicative breaks in a current flowing in said circuit, and a second member also rotated by said shaft to indicate relative direction. v

9. A structure according to claim 8 wherein the interrupter includes an. interruption gap positioned to cooperate with the orienting memher for the purpose of indicating a directional position of the gravity member.

10. A structure for surveying deep wells comprising an instrument adapted to be lowered into a well, devices in said instrument electrically sensitive to deviation from the vertical and to rotational displacement of the instrument housing, a circuit in which said devices are connected,

certain of said devices being adapted to modify the current in accordance with maximum deviation of the instrument from the vertical, and certain of said devices being adapted to modify said current -further for indication of the plane of maximum inclination with respect to the retational position of said housing.

11. A structure according to claim 10 including a compass indicative of relative direction.

12. A structure according to claim 10 including an earth inductor compass and means to correlate the compass reading with the position of the instrument housing.

13. A structure for surveying deep wells comprising an instrument adapted to be lowered into a well, devices in said instrument electrically sensitive to deviation from the vertical and to rotational displacement of the instrument'housing,

a circuit in which said devices are connected, certain of said devices being adapted to modify the current in accordance with maximum deviation of the instrument from the vertical, and certain of said devices being adapted to modify said current further for indication of the plane of maximum inclination with respect to the rotational position of said housing, an earth inductor compass carried in said housing, means for commutating the earth inductor current, means for synchronously driving said electrically sensitive de-- vices, and means for adjusting the phase-angle between said driving means and the earth inductor current to determine directional changes.

14. A well survey means comprising surface mechanism and an instrument adapted to be lowered into a well, a synchronous motor-generator in said surface mechanism, a synchronous driven motor in said instrument, devices in said instrument electrically sensitive to deviations from the vertical and to rotational displacement of the instrument, said devices being adapted to modify a current passed through said devices in accordance with deviation and rotational displacement respectively, means to receive said current modicurrent, and means to adjust for the phase angle between the synchronous drive and the earth inductor current.

15. A structure according to claim 14 in combination with means in the surface mechanism controlled by the receiving means for producing a record curve showing the modifications in the current from the electrically sensitive devices, and means for indicating and recording the phase angle adjustment for the'earth inductor current.

16. A structure according to claim 1 1 including a single set of conducting lines between the surface mechanism and the well instrument, and automatic switching means for selectively switching the earth inductor circuit and the sensitivedevices circuit in and out of connection with said lines.

17. A well survey instrument adapted to be lowered into a bore hole, comprising a pendulum, a mounting for said pendulum, means for positively driving said mounting through a cycle, and a resistance across which said pendulum swings during rotation of said mounting when the axis of the mounting is inclined.

18. A structure according to claim 17 including an earth inductor compass fororienting the plane of maximum inclination of the pendulum, in combination with" surface mechanism for recording the inclination and orientation.

19. A well survey instrument comprising a penstrument, means to commutate the earth inductor' es tense eei'oss Whigs zeteticn of said 2. s of the mounting is i' cim i eter for driving the pendulum me ereter fer energizing said syn hronote 'iQ'tGl", end means at the surface fer pendulum movement and erientetiem.

26. e1 eiisurvey ism L 11s for ineieming inelinatien ef the mile, 6. a em m inductor compass for erientLig means 21. A well survey mechanism "er" fer detecting an inclinatien eie, an earth inducter compass fer orientetien e1; said incline,- tion detecting means, a synchrenets motor 02:

driving the earth inducter co wes, and means for adjusting for a phase engie retention between the earth inductcr current the synehroneus meter drive current and means he reeer' said pnase reieticnshi a.

Weii survey mechanism inc EL EZEIELGE.

Lin

said eiineel, e syn :1wilting," orienting mews eertiz inductor c .l cezmeeteci fer at syncii enous meter, means in suit tor interrupting flew through said resistwce an ineheeefin c.

reiat 1e position of e penduiimi t0 the ement housing, se ture comprising means its car inductor eurrent, means eidgust tor, means to indicate phase an 'ie m c the comufeting means with respect ts ebroneus drive, means for receit'" energy representing pendulum converting it inte mecha ical e11e ereteel by the last (med "11g 2, record. indicative 

